Merge tag 'kgdb-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux

Pull kgdb updates from Daniel Thompson:
 "Pretty quiet this cycle. Just a couple of small fixes from myself both
  of which were reviewed by Doug Anderson to keep me honest (thanks)"

* tag 'kgdb-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
  kdb: Censor attempts to set PROMPT without ENABLE_MEM_READ
  kdb: Eliminate strncpy() warnings by replacing with strscpy()

kernel/debug/kdb/kdb_main.c

@@ -398,6 +398,13 @@ int kdb_set(int argc, const char **argv)
 	if (argc != 2)
 		return KDB_ARGCOUNT;
 
+	/*
+	 * Censor sensitive variables
+	 */
+	if (strcmp(argv[1], "PROMPT") == 0 &&
+	    !kdb_check_flags(KDB_ENABLE_MEM_READ, kdb_cmd_enabled, false))
+		return KDB_NOPERM;
+
 	/*
 	 * Check for internal variables
 	 */
@@ -1102,12 +1109,12 @@ static int handle_ctrl_cmd(char *cmd)
 	case CTRL_P:
 		if (cmdptr != cmd_tail)
 			cmdptr = (cmdptr-1) % KDB_CMD_HISTORY_COUNT;
-		strncpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+		strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
 		return 1;
 	case CTRL_N:
 		if (cmdptr != cmd_head)
 			cmdptr = (cmdptr+1) % KDB_CMD_HISTORY_COUNT;
-		strncpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
+		strscpy(cmd_cur, cmd_hist[cmdptr], CMD_BUFLEN);
 		return 1;
 	}
 	return 0;
@@ -1298,12 +1305,9 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
 		*(cmd_hist[cmd_head]) = '\0';
 
 do_full_getstr:
-#if defined(CONFIG_SMP)
+		/* PROMPT can only be set if we have MEM_READ permission. */
 		snprintf(kdb_prompt_str, CMD_BUFLEN, kdbgetenv("PROMPT"),
 			 raw_smp_processor_id());
-#else
-		snprintf(kdb_prompt_str, CMD_BUFLEN, kdbgetenv("PROMPT"));
-#endif
 		if (defcmd_in_progress)
 			strncat(kdb_prompt_str, "[defcmd]", CMD_BUFLEN);
 
@@ -1314,7 +1318,7 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
 		if (*cmdbuf != '\n') {
 			if (*cmdbuf < 32) {
 				if (cmdptr == cmd_head) {
-					strncpy(cmd_hist[cmd_head], cmd_cur,
+					strscpy(cmd_hist[cmd_head], cmd_cur,
 						CMD_BUFLEN);
 					*(cmd_hist[cmd_head] +
 					  strlen(cmd_hist[cmd_head])-1) = '\0';
@@ -1324,7 +1328,7 @@ static int kdb_local(kdb_reason_t reason, int error, struct pt_regs *regs,
 				cmdbuf = cmd_cur;
 				goto do_full_getstr;
 			} else {
-				strncpy(cmd_hist[cmd_head], cmd_cur,
+				strscpy(cmd_hist[cmd_head], cmd_cur,
 					CMD_BUFLEN);
 			}